diff --git a/lib/AST/FeatureSet.cpp b/lib/AST/FeatureSet.cpp
index 113d84d2e501e..d5b082461e7e5 100644
--- a/lib/AST/FeatureSet.cpp
+++ b/lib/AST/FeatureSet.cpp
@@ -103,7 +103,6 @@ UNINTERESTING_FEATURE(OpaqueTypeErasure)
 UNINTERESTING_FEATURE(PackageCMO)
 UNINTERESTING_FEATURE(ParserRoundTrip)
 UNINTERESTING_FEATURE(ParserValidation)
-UNINTERESTING_FEATURE(ParserDiagnostics)
 UNINTERESTING_FEATURE(ImplicitSome)
 UNINTERESTING_FEATURE(ParserASTGen)
 UNINTERESTING_FEATURE(BuiltinMacros)